1. Field of the Invention
The present invention relates to an apparatus for securing a toolholder within a clamping unit and, more specifically, relates to the use of a clamping unit activated by the motion of a longitudinally movable spring loaded lock rod to secure a toolholder within the base member, wherein the toolholder is secured along an axis different from that of the lock rod longitudinal axis.
2. Description of the Related Art
As an overview, metal working operations are typically performed using a cutting insert of a hard metal. Such an insert is mounted to a toolholder. The toolholder is secured either temporarily or permanently to a base member which is part of a machine such as a lathe or a milling machine.
Because of the extreme conditions under which they operate, cutting inserts must be replaced on a regular basis. In order to do this, the cutting insert must be removed from the toolholder. The economies of the metal working operation make it inefficient to shut a machine down for the length of time required to replace a cutting insert on a toolholder. It is more desirable to utilize a removable toolholder such that the entire toolholder with the accompanying cutting insert may be removed and replaced with another toolholder having a new cutting insert already in position on the toolholder.
With this in mind, the focus for efficiency becomes the ease and speed with which the toolholder may be replaced. This has been one of the motivating factors producing different commercial designs for quick change toolholders.
One example of such a design may be found in U.S. Pat. No. 4,747,735 entitled “Toolholder and Method of Releasably Mounting” by Erickson, et al., which is assigned to the Applicants of the subject invention and which is hereby incorporated by reference. This reference teaches a spring loaded reciprocating lock rod which is urged rearwardly by the springs to move locking members radially outwardly to secure a toolholder within a toolholder support member. In order to release the toolholder, the lock rod must be advanced so that the locking members are retracted and, furthermore, so that the toolholder is bumped from the toolholder support member. However, the locking member described in this patent must be activated axially and it is not capable of side activation.
U.S. Pat. No. 5,415,066 entitled “Apparatus for Holding a Toolholder Shank” by Erickson, et al., which is assigned to the Applicant of the subject invention and which is hereby incorporated by reference, discloses a side activation quick-change mechanism having a spring loaded longitudinally movable lock rod within a toolholder receiving member used to accept and secure therein a toolholder along the same longitudinal axis as that of the lock rod.
However, in an effort to conserve space, the inventors have realized that this parallel clamping system, wherein the toolholder extends from the toolholder receiving member along the longitudinal axis, could be reduced in length if the toolholder were to be mounted upon the side of the toolholder receiving member. This becomes an important factor on a machine which mounts clamping mechanisms on the periphery of its turret.